The overall aim of the research is to further the understanding of the relationships of drug use to sexual activity and premarital fertility among young men and women. Secondary analyses will be carried out on a representative national probability sample of young men and women from the Youth Cohort (NLS), the longitudinal survey conducted by Ohio State University. This national sample (N=12,069), first interviewed in 1979 at age 14-21, and reinterviewed at annual intervals through 1985, includes an overrepresentation of blacks (N=2,986), Hispanics (N=1,959) and disadvantaged whites (N=1,929), and members of the armed forces (N=1,215), as well as a large number school dropouts (N=3,402) (1984 unweighted sample sizes). Although originally designed as a study of the labor force experiences of young Americans, since 1982, participants have also been queried annually about their use of alcohol, sexual activity and fertility histories. In Wave VI (1984), at age 19-26, several questions on illicit drug use and cigarette smoking were included by the principal investigator under funding from NIDA. The specific aims of the research are to assess: (1) the relationships between the use of legal and illegal drugs (alcohol, cigarettes, marijuana and other illicit drugs) and fertility behavior, including sexual activity, contraceptive practices and childbearing among young men and women, and premarital pregnancies among young women; (2) the effects of the use of alcohol, cigarettes and illicit drugs on the health behavior of mother and child, in particular prenatal maternal and postnatal infant medical care, birth outcome and breastfeeding; (3) limited aspects of the effects of alcohol, cigarettes and illicit drug use on child- rearing practices of men and women; (4) the contrasts and similarities of effects outlined in (2) and (3) separately among adolescents and young adults. In addition to cross-tabulations and regression analyses, modified Guttman scaling will be used to investigate developmental sequences of involvement in drug use and sexual activity. The dynamic relationships between drug use and sexual behavior will be explored through event history analysis. The NLS provides an opportunity to investigate the relationships between two health compromising behaviors among groups of young people known to be at an especially high risk for experiencing premarital pregnancies.